A head assembly for use in a compressor having a compression chamber for compressing a fluid is disclosed. More specifically, the head assembly includes an improvement for retaining oil in the compressor.
Vehicle air-conditioning systems include a compressor that compresses and superheats refrigerant. The refrigerant exits the compressor and continues first to a condenser and then to an expander. From the expander, the refrigerant enters an evaporator and then returns to the compressor to begin the cycle again. Occasionally, the air-conditioning system will include either an accumulator/dehydrator (A/D) or a receiver/dehydrator (R/D). The purpose of these devices is to remove moisture from the refrigerant and to store a reserve charge of the system until it is needed upon demand.
Generally, the compressor is a belt-driven pump that includes at least one compression chamber and a head assembly comprising a manifold housing, an intake port and an exhaust port. The manifold housing further defines a suction chamber and a discharge chamber. The intake port guides the refrigerant from the evaporator to the suction chamber. The suction chamber subsequently guides the refrigerant from the intake port to the compression chamber where it is compressed. The compressed refrigerant is received in the discharge chamber and from the discharge chamber the refrigerant is exhausted to the exhaust port. The refrigerant is then guided from the exhaust port to the condenser to begin the cycle again.
Prior art head assemblies experience oil retention problems and difficulty protecting the compressor from wear. Oil retention is crucial for lubricating the working components of the compressor. Retaining oil in the compressor increases the life of the compressor.
Prior art head assemblies, such as those shown in U.S. Pat. No. 6,010,314 to Kobayashi et al. and U.S. Pat. No. 6,179,578 to Kayukawa et al. provide oil separation mechanisms in an attempt to increase oil retention within the compressor. The ""578 patent to Kayukawa et al. utilizes a plug structure for separating the oil from the refrigerant as the refrigerant enters the exhaust port. The plug structure complicates manufacture of the head assembly and increases the cost thereof.
The ""314 patent to Kobayashi et al. includes an oil retention housing defining a oil retention chamber wherein the housing is mounted to an outside wall of the compressor. The refrigerant and oil exit the discharge chamber to the oil retention chamber and gravity pulls the oil toward a bottom end of the oil retention chamber. A supply line connects the oil retention chamber to a lubrication chamber, which stores the oil in the compressor for lubricating the components. One disadvantage of the Kobayashi apparatus is that the oil retention chamber requires additional structure with the existing head assembly and compressor thereby increasing costs and hampering ease of manufacture. Furthermore, the oil retention chamber must be located above the compressor, posing packaging issues and the fixed orifice supply line results in performance losses within the air-conditioning system.
Both the ""578 patent to Kayukawa et al. and the ""314 patent to Kobayashi et al. include head assemblies wherein the discharge chamber substantially surrounds the suction chamber and is unobstructed in relation to the exhaust port. This configuration limits oil retention within the compressor by not providing a sufficient barrier between the discharge chamber and the exhaust port. Additionally, both the ""578 patent to Kayukawa et al. and the ""314 patent to Kobayashi et al. require additional structures that complicates manufacture of the head assembly. As a result, there is a need for a head assembly that increases oil retention in the compressor without adding additional, unnecessary structural components or separate structures, resulting in easier manufacturing and a more economical head assembly.
In one aspect of the present invention, a head assembly for use in a compressor having oil for lubrication and defining a first compression chamber for compressing a fluid is provided. The head assembly includes a manifold housing defining an intake port, an exhaust port and a control valve port. The manifold housing comprises an outer wall, a first inner wall and a second inner wall wherein the outer wall and the first inner wall define a suction chamber in fluid communication with the intake port for receiving the fluid from the intake port and guiding the fluid to the first compression chamber. The first inner wall and the second inner wall define a discharge chamber for receiving the fluid from the first compression chamber. An aperture is formed in the first inner wall for guiding the fluid and the oil from the discharge chamber to the control valve port. The second inner wall is internal to the outer wall and the first inner wall and defines an exit chamber for guiding the fluid from the discharge chamber to the exhaust port. The exit chamber is in fluid communication with the exhaust port and the second inner wall defines a partition between the aperture and the exhaust port such that the oil pools in the discharge chamber between the first inner wall and the second inner wall thereby retaining the oil in the compressor to lubricate the compressor.
In another aspect of the present invention, a compressor assembly for compressing a fluid and having oil for lubrication is provided. The compressor includes a compressor housing defining a compression chamber for compressing the fluid. A piston is disposed in the compression chamber and is slidably movable within the compression chamber. A manifold housing is coupled to the compressor housing and defines an intake port, an exhaust port and a control valve port. The manifold housing comprises an outer wall, a first inner wall and a second inner wall. The outer wall and the first inner wall define a suction chamber in fluid communication with the intake port for receiving the fluid from the intake port and guiding the fluid to the compression chamber. The first inner wall and the second inner wall define a discharge chamber for receiving the fluid from the compression chamber. An aperture is formed in the first inner wall for guiding the fluid and the oil from the discharge chamber to the control valve port. The second inner wall is internal to the outer wall and the first inner wall and defines an exit chamber for guiding the fluid from the discharge chamber to the exhaust port. Additionally, the exit chamber is in fluid communication with the exhaust port and the second inner wall defines a partition between the aperture and the exhaust port such that the oil pools in the discharge chamber between the first inner wall and the second inner wall thereby retaining the oil in the compressor to lubricate the compressor.
Accordingly, the advantage of the subject invention described above is the ability of the subject invention to effectively increase oil retention within the compressor without adding unnecessary structure or plugs to the head assembly. More specifically, the advantage of the subject invention is the configuration of the second inner wall wherein the second inner wall provides the barrier between the aperture and the exhaust port. This barrier is critical in pooling the oil in the manifold housing prior to being discharged to the control valve port. Furthermore, the subject invention is easy to manufacture relative to the prior art head assemblies and the subject invention provides additional advantages that will become apparent from the description of the preferred embodiment including higher efficiency and increased performance.